Relationships of birth weight and pre-nursing concentrations of serum albumin to survival and growth rate in swine.

Data from 29 litters of swine were analyzed to estimate the relationships of birth weight and pre-nursing concentrations of serum albumin to survival and daily gain from birth to 14 d and from 14 to 28 d. Means and standard deviations of birth weight and serum albumin were calculated within each litter and used as analytical units. Positive linear partial regression coefficients were detected for effects of serum albumin on birth weight (P less than .01) and daily gains (P less than .05). As both serum albumin and birth weight increased, survival also increased but at a decreasing rate (P less than .05). Survival decreased as the standard deviations of serum albumin (P less than .05) and the birth weight (P less than .10) increased. Daily gain from 14 to 28 d of age increased (P less than .10) as the standard deviation of serum albumin varied above or below about .5 mg/ml. The linear effect of birth weight on daily gain from birth to 14 d of age was positive (P less than .01), whereas daily gain from 14 to 28 d of age increased as birth weight varied above or below about 1.3 kg (P less than .01). Daily gains during the first and second periods also increased as the standard deviation of birth weight varied above or below .3 kg (P less than .05) and .25 kg (P less than .001), respectively. Fitting birth weight and serum albumin simultaneously into the statistical model accounted for 57% of the variation in survival, a level at least twice as great as previously reported. It is speculated that use of a marker of physiological maturity, such as pre-nursing concentrations of serum albumin, might facilitate selection for survival.